Interannual sedimentary effluxes of alkalinity in the southern North Sea: model results compared with summer observations

摘要: Abstract. For the sediments of central and southern North Sea different sources alkalinity generation are quantified by a regional modelling system for period 2000–2014. this purpose formerly global ocean sediment model coupled with pelagic ecosystem is adapted to shelf sea dynamics, where much larger turnover rates than in open deep occur. To track changes due nitrogen-related processes, was extended state variables particulate organic nitrogen (PON) ammonium. Directly measured fluxes those derived from Ra isotope flux observation into reproduced system, but calcite building dissolution underestimated. Both cancel out terms consumption. Other simulated processes altering sediment, like net sulfate reduction, denitrification, nitrification, aerobic degradation, compare well corresponding observations. Most these exhibit strong positive gradient coast, large rivers drain nutrients matter. Atmospheric deposition also shows towards land supports sediments. An additional source spatial variability introduced use 3-D heterogenous porosity field. Due realistic variations (0.3–0.5) vary about 4 %. The strongest impact on interannual exhibited temporal varying inputs directly governing nitrate concentrations coastal bottom water, thus providing necessary benthic denitrification. Over time investigated effluxes decrease supply rivers.